Hoopla!

The main problem I have with the rails default ./config/database.yml format is that it’s not DRY. Here’s an example of a default database config:

development:
  adapter: mysql
  database: development_db
  username: username
  password: password
  sochost:  localhost
test:
  adapter: mysql
  database: testing_db
  username: username
  password: password
  sochost:  localhost
production:
  adapter: mysql
  database: production_db
  username: username
  password: password
  sochost:  localhost

Now, thanks to the Typo team (who have also made this blog possible), we have an alternative format that you can use to keep the redundancies out of your file:

login: &login
  username: username
  password: password
  adapter:  mysql
  host:     localhost

development:
  database: development_db
  <<: *login

test:
  database: testing_db
  <<: *login

production:
  database: production_db
  <<: *login

If this isn’t slick enough for you, Doug Alcorn has improved upon this by letting you change the login details for each host that you might run this application on. His code:

login: &login
  username: username
  password: password
  adapter:  mysql
  host:     localhost

# replace the above login details with information from ./config/dblogin.yml
<%= file = File.join(RAILS_ROOT, "config", "dblogin.yml")
    IO.read(file) if File.exist?(file) %>

development:
  database: development_db
  <<: *login

test:
  database: testing_db
  <<: *login

production:
  database: production_db
  <<: *login

And then you can have a separate file next to database.yml called dblogin.yml – and it can be different for each host. Here’s an example of what dblogin.yml could look like:

login: &login
  username: danger
  password: jesus_was_probably_good_at_juggling
  adapter:  mysql
  host:     localhost